An Overview of Acoustical Plaster

Photography Courtesy of Fellert

Although plaster has been used since the ancient world, acoustical plaster has been gaining momentum in the industry over the last couple of decades due to its sound absorption properties and seamless appearance. Acoustical plaster has an array of inherent advantages that include flexibility, ease of installation, a lightweight design, and an unlimited range of sound-absorbing finishes. The information that follows explores a brief overview of acoustical plaster.

Characteristics

Acoustical plaster is typically made of an aggregate such as crushed marble or crushed glass, although there are also ways of using materials such as cotton. Unlike traditional plaster, acoustical plaster has microscopic pores in the surface which allows sound to travel through the plaster and into an acoustical board that breaks up the sound. “What [the pores] do is allow the sound to go through [the surface] and into the backer board, which absorbs the majority of the sound,” says Nicolas Fulton of Fellert. “It’s the board that does the work.”

Photography Courtesy of Fellert

While acoustical panels are used throughout architecture and design, the advantage of acoustical plaster is that it provides a different appearance from other types of acoustical tiles and wallcoverings. Fulton says, “You could have tile absorb the sound, but you’d have joint lines everywhere. The whole idea of acoustical plaster is, how do we cover these joint lines so that the surface looks seamless and monolithic, and still get the sound absorption?” Acoustical plaster allows architects and designers to construct a smooth, seamless surface without the reverberation that occurs with traditional plaster or other solid surface materials. Although acoustical plaster isn’t able to take the same type of direct impact that traditional plaster can, breaks and dents can be patched over.

Where is Acoustical Plaster Installed?

Because acoustical plaster is more expensive than other surfacing types at around $40 per square foot, the projects where it is used are typically high-end commercial interiors and the occasional multi-unit residential building. “It’s really only used when that seamless look is just as important as the super high sound absorption coefficient.” These locations include museums, libraries, performance halls, and high-end restaurants.

Photography Courtesy of Fellert

However, because acoustical plaster is more expensive than other surfacing types and easier to break if something runs into it, it’s usually installed on the ceiling of the space or upper walls higher than 6 feet where it won’t come in contact with objects. “Because acoustical plaster systems are porous and open, they can’t take a lot of direct impact. If you use traditional plaster, you can use that all the way down to the floor because you can hit plaster pretty hard before it cracks. Acoustical plaster doesn’t take impact that well. The industry suggests it be installed on upper walls and ceilings,” explains Fulton. Additionally, because it’s a more fragile system that involves first installing the acoustical board backing and then the porous plaster, it requires a certified contractor to ensure it’s been installed correctly.

The Latest in Acoustical Plaster Technology

Today, technology around acoustical plaster has focused on new aesthetics, giving architects and designers more freedom with how the space will look. Fulton says it’s only been in the last three to five years that new designs have been brought to the market. While options usually include whether you want a smooth, lightly textured or textured finish, acoustical plaster can now be made to look like natural materials or have color added to it.

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